Avoid Dynamic Node Removal

These are the basic guidelines regarding nodes and edges:

Avoid dynamic node removal

Adding edges and nodes is supported

Removing edges is supported

It is possible to add new nodes and edges and to remove old edges from a flow graph as nodes are actively processing messages in the graph. However, removing nodes is discouraged. Destroying a graph or any of its nodes while there are messages being processed in the graph can lead to premature deletion of memory that will be later touched by tasks in the graph causing program failure. Removal of nodes when the graph is not idle may lead to intermittent failures and hard to find failures, so it should be avoided.